TWI510524B - Inductance element - Google Patents

Description

Inductive component

The present invention relates to an inductive component in which a coil is embedded in a magnetic core.

In the inductance element in which the coil is embedded in the magnetic core, the metal plate terminal extending from the coil is exposed on the outer surface of the magnetic core, and the metal plate terminal is usually soldered and mounted on the pad portion of the external circuit formed on the wiring substrate.

In the small inductance element, since the size of the coil is small, the terminal of the metal plate protruding to the outside of the magnetic core is small, and the connection area for soldering to the external circuit cannot be sufficiently ensured, and the conduction reliability cannot be ensured, and The problem of the fixed strength of the wafer components on the substrate is also reduced.

In the wafer component described in Patent Document 1 below, a covered wire is wound around a winding groove of a core, and a coil is provided, and the core and the coil are covered with an insulating resin material. The coil is electrically joined to the metal plate terminal, and the metal plate terminal is formed of a free insulating resin material, and the side surface of the resin is extended to the outside, and the front end is cut by the side end of the exterior resin. A conductive paste is coated on the entire side of the exterior resin and in the vicinity thereof, and is electrically coupled between the conductive paste and the metal plate terminal.

In the wafer portion described in Patent Document 1, the conductive paste that is electrically connected to the metal terminal is entirely coated on the side surface of the exterior resin, and the conductive paste is used as a substantial terminal portion for connection. The connection area required for external circuit soldering.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 2-235305

In the wafer component described in Patent Document 1, since an epoxy resin or a diallyl resin is used as the insulating resin material constituting the exterior resin, heating is performed for other purposes than curing of the material. In the case where the environment in which the wafer component is used is at a high temperature, there is a problem that stress is applied to the core covered by the exterior resin due to deformation of the insulating resin material due to heat, and deformation occurs, thereby causing magnetic properties. There are changes in the aspects.

Therefore, as the exterior resin, it is also considered to use an insulating resin material which is less deformed by heat, but in this case, the conductive paste and the external conductive paste are not different from the bonding agent forming the terminal portion for the connection. The adhesiveness of the resin is contained, the conductive paste is easily peeled off, the reliability of conduction with an external circuit cannot be ensured, and the fixing strength of the wafer component on the wiring substrate is also lowered.

Therefore, an object of the present invention is to provide an inductance element in which a coil is embedded in a magnetic core, and is stabilized by selecting a material covering the resin layer so as to prevent a large stress from acting on the core body from the cover resin layer. Magnetic properties. Further, an object of the present invention is to provide an inductance element which ensures adhesion between a terminal conductive layer formed on a surface of a core body and a core body.

In order to solve the above problems, the inductor element of the first aspect of the present invention has a coil embedded in the magnetic core, and the inductor element is characterized in that the magnetic core has a core body including magnetic powder and is formed by press molding, and Covering the resin layer on the outer surface of the core body, at least a part of the metal terminal portion which is electrically connected to the coil is not covered by the covering resin layer on the outer surface of the core body, but is exposed, and a conductive material is formed on the surface of the magnetic core a terminal conductive layer composed of a binder resin, and a terminal conductive layer and a cover resin layer and a terminal portion The cover resin layer is formed of an epoxy-modified fluorenone resin.

By forming an overcoat resin layer covering the outer surface of the core body of the magnetic core by using an epoxy-modified fluorenone resin, even if a temperature change occurs, a large stress is not applied to the magnetic core, and stable magnetic characteristics can be obtained. Further, the adhesion to the terminal conductive layer formed on the surface of the core body can be ensured.

In the inductor element of the second aspect of the present invention, a coil is embedded in the magnetic core, and the inductor element is characterized in that the magnetic core has a core body including magnetic powder and is formed by press molding, and covers the core body. The surface covering resin layer, at least a part of the metal terminal portion which is electrically connected to the coil is not covered by the covering resin layer on the outer surface of the core body, but is exposed, and is formed of a conductive material and a binder resin on the surface of the magnetic core. The terminal conductive layer, the terminal conductive layer is bonded to the cover resin layer and the terminal portion, and the cover resin layer is formed of a heat resistant polyester resin.

By forming a cover resin layer covering the outer surface of the core body of the magnetic core by using a heat-resistant polyester resin, even if a temperature change occurs, a large stress is not applied to the magnetic core, and stable magnetic characteristics can be obtained, and further, The adhesion between the conductive layer and the terminal formed on the surface of the core body is ensured.

In the above-described first aspect of the inductor element, it is preferred that the epoxy-modified fluorenone resin comprises an fluorenone epoxy varnish.

In the inductance element of the second aspect described above, it is preferred that the heat resistant polyester resin comprises a phenol-modified alkyd resin or a polyester fluorenone.

In the inductance element of the present invention, it is preferable that the adhesive resin of the terminal conductive layer is an epoxy resin.

By using an epoxy resin, the adhesion to the covering resin layer can be improved.

In the inductor element of the present invention, it is preferable that the terminal portion is a strip-shaped body whose surface is exposed on the outer surface of the core body to be bonded to the terminal conductive layer. By performing surface bonding, the bonding area between the terminal and the terminal conductive layer can be increased, and the bonding resistance can be reduced.

According to the present invention, an inductance element can be provided, in which an inductance element of a coil is embedded in a magnetic core, and an epoxy-modified fluorenone resin or a heat-resistant polyester resin is used to form a cover covering an outer surface of the core body of the magnetic core. By the resin layer, even if a temperature change occurs, the covering resin layer does not impart a large stress to the magnetic core, and has stable magnetic properties. Further, according to the present invention, by forming the cover resin layer with an epoxy-modified fluorenone resin or a heat-resistant polyester resin, it is possible to ensure adhesion to the terminal conductive layer formed on the surface of the core body.

1‧‧‧Inductive components

10‧‧‧ coil

12‧‧‧Coil insulation

15, 18‧‧‧ Terminals

15a, 18a‧‧‧ with surface

15b, 18b‧‧‧ front face

20‧‧‧ magnetic core

21‧‧‧ core body

21a‧‧‧lower surface

21b‧‧‧ side

21c‧‧‧Steps Department

22‧‧‧ Covering resin layer

22b‧‧‧ recess

25‧‧‧ gap

42‧‧‧Terminal Conductive Layer

43‧‧‧ Hole Department

101‧‧‧Strip

101a‧‧‧ Both ends

O‧‧‧ center axis

Fig. 1 is a perspective view showing the configuration of an inductance element according to an embodiment of the present invention.

Fig. 2 is a bottom plan view showing the configuration of the inductance element of Fig. 1.

Fig. 3 is a cross-sectional view showing the structure of the inductance element of Fig. 1 taken along line III-III of Fig. 1.

Fig. 4 is an enlarged partial cross-sectional view showing a portion of Fig. 3 in an enlarged manner.

Fig. 5 is a graph showing the relationship between the material covering the resin layer and the bonding strength in the examples and the comparative examples.

Hereinafter, an inductance element according to an embodiment of the present invention will be described in detail with reference to the drawings.

Hereinafter, an example in which the coil and the terminal portion are integrated will be described. However, the present invention is also applicable to a form in which the coil and the terminal portion are independent from each other and electrically connected to each other.

As shown in FIG. 1, in the inductance element 1 of the present embodiment, the coil 10 is embedded in the magnetic core 20. 1 shows a configuration of the inductance element 1 and a perspective view in which the lower surface 22 of the magnetic core 20 faces the upper side. In FIG. 1, the coil 10 embedded in the magnetic core 20 is indicated by a solid line, and the outer surface of the magnetic core 20 is indicated by a broken line.

As shown in FIG. 1, the coil 10 is formed by winding a strip-shaped conductive body 101 having a rectangular cross section in an elliptical shape around a center line O. Furthermore, the shape of the coil 10 is not limited to an elliptical shape, and It can be a true circle, and the industry can choose it properly.

The end portions 101a, 101a of the strip 101 forming the coil 10 are bent along a plane parallel to the central axis O, and further, the front ends of the respective end portions 101a, 101a extend along the lower surface 22 of the magnetic core 20. The method is bent to form a pair of terminal portions 15, 18. In the present embodiment, the coil 10 is integrally formed with the pair of terminal portions 15, 18. The strip 101 wound into the coil 10 is formed of, for example, copper.

As shown in FIG. 4, a coil insulating layer 12 is formed on the surface of the strip 101. The coil insulating layer 12 is, for example, a two-layer structure in which a fusion layer such as nylon is superposed on the surface of an insulating resin layer. In FIG. 4, although the coil insulating layer 12 is formed on the surface of the first terminal portion 15, the other portion of the strip 101 may have the same cross-sectional structure as the first terminal portion 15, that is, a coil is formed on the surface. Insulation layer 12.

As shown in FIG. 1, the magnetic core 20 is formed in a substantially cubic shape. As shown in FIG. 3, the magnetic core 20 includes a core body 21 which is a powder compact obtained by press molding a magnetic powder and a binder resin, and a cover resin layer 22 which covers the outer surface of the core body 21 to reinforce the core body 21. .

As shown in FIG. 1, FIG. 2, and FIG. 3, the belt surfaces 15a, 18a of the first terminal portion 15 and the second terminal portion 18 are exposed on the lower surface 21a of the core body 21 (the lower surface of the magnetic core 20), and are located at The lower surface 21a of the core body 21 is substantially the same surface. Further, the both end portions 101a of the strip 101 from the coil 10 to the first terminal portion 15 and the second terminal portion 18 are also located on substantially the same surface as the side surface 21b of the core body 21.

As shown in FIGS. 3 and 4, each of the terminal portions 15 and 18 is disposed in the recess 22b, and the recess 22b is formed in a shape substantially the same as the shape of the terminal portion formed on the lower surface 21a of the core body 21. For example, in the powder molding step, the magnetic core material supplied to the inside of the cavity is fixed with a fixed pressing force in a state in which the coil 10 and the terminal portions 15 and 18 are disposed inside the cavity (not shown). The magnetic portion (the magnetic powder and the binder resin) is pressed and heated to form the concave portion 22b.

As shown in FIG. 4, the coil insulating layer 12 is not formed on the front end faces 15b and 18b of the terminal portions 15, 18. The reason for this is that the front end faces 15b and 18b correspond to the cut faces when the covered wires are cut.

As shown in FIG. 4, a gap 25 is formed between the end faces 15b and 18b of the terminal portions 15 and 18 and the step portion 21c of the core body 21. The gap 25 is formed by springback of the terminal portions 15, 18 after pressurization in the powder molding step.

As shown in FIGS. 3 and 4, the entire outer surface of the core body 21 is coated with the cover resin layer 22. As shown in FIG. 4, a portion of the cover resin layer 22 is also filled into the above gap 25. Since the belt surfaces 15a and 18a of the first terminal portion 15 and the second terminal portion 18 are exposed on the lower surface 21a of the core body 21, the first terminal portion 15 and the second terminal portion 18 are surface-engaged with the cover resin layer 22.

As shown in FIG. 2, a pair of terminal conductive layers 42 are formed on the lower surface of the magnetic core 20 at intervals in the left-right direction of the drawing. The terminal conductive layer 42 is formed in a strip shape on the outer surface of the above-mentioned cover resin layer 22 covering the lower surface of the magnetic core 20. As shown in FIG. 2, FIG. 3, and FIG. 4, a hole portion 43 obtained by removing one portion of the cover resin layer 22 is formed in a portion of the cover resin layer 22 that overlaps the terminal portions 15, 18, and covers the terminal portion 15. The coil insulating layer 12 of 18 is also removed at a portion corresponding to the hole portion 43. The terminal conductive layer 42 is joined to and electrically connected to the tape surfaces 15a and 18a of the terminal portions 15, 18 at the hole portion 43. Since the terminal portions 15, 18 are surface-bonded to the terminal conductive layer 42, the bonding resistance is small, and the terminal portions 15, 18 and the terminal conductive layer 42 are also firmly joined.

The terminal conductive layer 42 is formed in a strip shape over the entire length of the left and right side portions of FIG. 2 (the total length in the vertical direction of the drawing), and the terminal is electrically conductive as compared with the area of the terminal portions 15, 18 located on the lower surface of the magnetic core 20. The area of layer 42 is formed to be sufficiently large. Most of the terminal conductive layer 42 is bonded to the surface of the cover resin layer 22, and only a part of the hole portion 43 is joined to the tape surfaces 15a, 18a of the terminal portions 15, 18.

The terminal conductive layer 42 is composed of a conductive material and a binder resin. Terminal conductive layer 42 The binder resin is, for example, an epoxy resin, and the conductive material is made of, for example, silver, specifically, silver paste or the like.

Here, the terminal portions 15 and 18 which are extended from the coil 10 are formed long without forming the terminal conductive layer 42 made of silver paste or the like, and the area required for soldering can be secured, but if it is increased, When the terminal portions 15 and 18 are bent on the outer surface of the magnetic core 20, the force acting on the magnetic core 20 from the terminal portions 15 and 18 is excessively increased, and the magnetic core 20 is easily cracked. And so on. In the case where the magnetic core 20 is a powder-forming core formed of a magnetic powder and a binder resin, if a large force is applied to the magnetic core 20, damage is likely to occur, and further, the size of each side is about 1 to 2 mm. In the case of a small magnetic core, it is particularly easy to cause damage to the magnetic core 20.

As shown in FIGS. 3 and 4, the concave portion 22b for arranging the terminal portions 15, 18 must be formed on the outer surface of the magnetic core 20. However, if the terminal portions 15, 18 are grown, it is necessary to largely ensure the area of the concave portion 22b. Since the magnetic powder is not present in the concave portion 22b, if the concave portion 22b is enlarged, the volume occupied by the magnetic powder of the magnetic core 20 is reduced, and there is a problem that the inductance cannot be increased.

In the present embodiment, by forming the terminal conductive layer 42 by using silver paste or the like, even if the length and area of the terminal portions 15 and 18 extended from the coil 10 are small, the area to be soldered to the external circuit can be largely ensured. Since the terminal portions 15 and 18 can be made small, when the terminal portions 15 and 18 are formed, the force applied to the magnetic core 20 can be reduced, and the magnetic core 20 is less likely to be damaged. Moreover, since the concave portion 22b can be made small, the inductance of the magnetic core 20 can be prevented from being lowered.

Further, even if the area of the terminal portions 15 and 18 is small, as shown in FIG. 2, since the large-area terminal conductive layer 42 can be formed over the entire length of both side portions of the lower surface of the magnetic core 20, it is possible to improve the external portion. The reliability of the conduction of the circuit can improve the fixing strength of the inductance element 1 on the wiring substrate. Therefore, it is most suitable when a small-sized powder forming core having a size of about 1 to 2 mm is used.

The core body 21 is a powder forming core formed by pressurizing the magnetic powder and the binder resin in the cavity in a state where the coil 10 is provided in the cavity of the molding die. The magnetic powder is a magnetic alloy powder, and is, for example, a powder of a Fe-based amorphous alloy containing Fe as a main component and containing various metals such as Ni, Sn, Cr, P, C, B, and Si, and is powdered by a water atomization method. The binder resin is an acrylic resin, an anthrone resin, an epoxy resin or the like.

The cover resin layer 22 is an electrically insulating resin layer and is formed using an epoxy-modified fluorenone resin or a heat-resistant polyester resin. The epoxy-modified fluorenone resin is, for example, an fluorenone epoxy varnish. The heat resistant polyester resin is, for example, a phenol-modified alkyd resin or a polyester fluorenone. Further, the cover resin layer 22 is suitable to have a viscosity capable of immersing in the outer surface of the magnetic core 20. By immersing the cover resin layer 22 from the outer surface of the core body 21 to a specific depth, the mechanical strength of the surface of the core body 21 of the powder compact can be reinforced by the cured cover resin layer 22.

As the magnetic powder, a Fe-based amorphous alloy is preferably used. In this case, after the core body 21 is formed, annealing is performed at a temperature of several hundred ° C to remove magnetostriction, but in the annealing step, the core resin is thermally decomposed by heat or the like. 21 is easy to become brittle. Therefore, it is particularly necessary to cover the resin layer 22 for the powder-forming core to be annealed.

If the epoxy resin-modified fluorenone or heat-resistant polyester resin is used to form the cover resin layer 22 covering the outer surface of the core body 21, excessive stress is not applied to the core body 21 from the cover resin layer 22 even if a temperature change occurs. The deformation and the magnetic properties of the core body 21 can be stabilized.

Further, by forming the cover resin layer 22 with an epoxy-modified anthrone or a heat-resistant polyester resin, and using an epoxy resin as the binder resin used in the terminal conductive layer 42, the cover resin layer 22 and the terminal can be made conductive. The adhesion of layer 42.

Hereinafter, examples will be described.

(Example 1)

Covering resin layer: anthrone epoxy varnish (modified fluorenone resin) ES-1001N (Shin-Etsu Chemical Industrial society)

Add solvent (xylene, butanol, diacetone alcohol) and dilute to a viscosity of 10mPa. s.

Hardening conditions: After drying at 70 ° C for 30 minutes, it was cured by heating at 200 ° C for 45 minutes.

(Example 2)

Covering resin layer: fluorenone epoxy varnish (modified fluorenone resin) ES-1023 (manufactured by Shin-Etsu Chemical Co., Ltd.)

Add solvent (xylene, diacetone alcohol) and dilute to a viscosity of 200mPa. s.

Hardening conditions: After drying at 70 ° C for 30 minutes and drying, it was cured by heating at 200 ° C for 45 minutes.

(Example 3)

Covering resin layer: anthrone polyester varnish (polyester ketone) KR-5230 (manufactured by Shin-Etsu Chemical Co., Ltd.)

Add solvent (propylene glycol monomethyl ether acetate: PGMAC) and dilute to a viscosity of 300mPa. s.

Hardening conditions: After drying at 70 ° C for 20 to 30 minutes, the mixture was dried, and then heated at 200 ° C for 45 minutes to be hardened.

(Example 4)

Covering resin layer: heat-resistant polyester resin (phenol-modified alkyd resin) H550 (manufactured by MEIDEN CHEMICAL)

Add solvent (xylene) and dilute to a viscosity of 350mPa. s.

Hardening conditions: After heating at 135 ° C for 60 minutes and drying, it was cured by heating at 180 ° C for 150 hours.

(Example 5)

Covering resin layer: anthrone modified epoxy varnish TSR194 (manufactured by MOMENTIVE PERFORMANCE MATERIALS JAPAN)

Add solvent (xylene and ethylbenzene) and dilute to a viscosity of 180mPa. s.

Hardening conditions: After drying at 70 ° C for 20 to 30 minutes, the mixture was dried and then cured by heating at 150 ° C for 30 minutes.

(Comparative Example 1)

Covering resin layer: methyl phenyl fluorenone resin (straight silicone resin) KR-271 (manufactured by Shin-Etsu Chemical Co., Ltd.)

Add solvent (xylene) and dilute to a viscosity of 180mPa. s.

Hardening conditions: After drying at 70 ° C for 30 minutes and drying, it was cured by heating at 250 ° C for 60 minutes.

(Comparative Example 2)

Covering resin layer: methyl ketone ketone resin (linear fluorenone resin) KR-242A (manufactured by Shin-Etsu Chemical Co., Ltd.)

Add solvent (toluene, isopropanol) and dilute to a viscosity of 12mPa. s.

Hardening conditions: After heating at 70 ° C for 30 minutes to dry the solvent, it was heated at 200 ° C for 35 minutes to be hardened.

(Comparative Example 3)

Covering resin layer: two-component epoxy adhesive AZ15 (main agent): HZ15 (hardener) = 100:30 (manufactured by NAGASE CHEMTEX)

Hardening conditions: After heating at 70 ° C for 20 to 30 minutes to dry the solvent, it was heated at 180 ° C for 60 minutes to be hardened.

The subsequent strength and the inductance change rate (L change rate) were measured for the above samples.

<Continue strength>

The cover resin layer corresponding to the cover resin layer 22 is entirely coated on the upper surface of the copper plate (thickness 0.1 mm × width 25 mm × length 100 mm) corresponding to the terminal portions 15 and 18 described above, and on the basis of this, two prepared A sample having a terminal conductive layer corresponding to the above-mentioned terminal conductive layer 42 is coated with a pen having a width of 25 mm × a length of 12.5 mm, so that two tests are performed. The terminal conductive layers of the material contact each other and harden, thereby preparing a sample for use in the test.

Here, silver paste H9108 (adhesive: epoxy resin) (manufactured by NAMICS) was used as the terminal conductive layer, and it was cured by heating at 175 ° C for 1 hour.

The adhesive strength was measured using Condition Test No. 15 (stretch shear) using a tensile tester (Model 3365 (manufactured by INSTRON)).

Fig. 5 is a graph showing the relationship between the material covering the resin layer and the bonding strength in the examples and the comparative examples. The adhesive strength as referred to herein is the tensile strength (maximum load at the time of shear fracture) (unit MPa) measured by the above tensile tester. Three measurements were performed, and the average value (unit MPa) shown below is shown in FIG.

Example 1: 0.825

Example 2: 0.961

Example 3: 1.194

Example 4: 1.359

Comparative Example 1: 0.324

Comparative Example 2: 0.784

According to the results, in Examples 1 to 4, the subsequent strength was 0.8 MPa, and sufficient adhesion between the covering resin layer and the terminal conductive layer was confirmed. On the other hand, in Comparative Examples 1 and 2, when the strength is less than 0.8, when a linear fluorenone resin is used for the cover resin layer and an epoxy resin is used for the adhesive resin of the terminal conductive layer, Unable to ensure confidentiality.

Further, in the inspection of the visual observation, in Comparative Example 1, interfacial peeling occurred between the cover resin layer and the terminal conductive layer, and in Comparative Example 2, the cover resin layer was easily peeled off from the copper plate.

<Inductance change rate>

Preparation of Sample: A magnetic powder composed of a Fe-based amorphous alloy having a composition of Fe _71.4 Ni ₆ P _10.8 C _7.8 B ₂ Cr ₂ and a binder resin (acrylic resin) were used to prepare a core body in which a coil was embedded. The dimension is a width dimension corresponding to the longitudinal direction of the terminal conductive layer of 0.6 mm, a width dimension orthogonal thereto of 2 mm, and a thickness dimension of 0.04 mm. The width of the terminal conductive layer is 0.6 mm, and the contact area between the terminal conductive layer and the terminal portion is 0.12 mm ² or more.

For the coil, the strip-shaped wire has a width of 0.28 mm, a thickness of 0.03 to 0.1 mm, and a number of turns of 3.5 to 14.5 turns.

Measurement method: a current of 0.5 mA is applied to a coil of an inductance element composed of a coil and a core body, and an initial inductance measured by an inductance-capacitance resistance tester (LCR meter) is set to L0, and each cover resin layer is to be used. The inductance measured after covering the core body was set to L1, and the inductance of the inductor element covered with the cover resin layer was set to L2 after being placed in an environment of 60 ° C and a relative humidity of 95% for 300 hours.

L1/L0×100 (%) was used as the coating degradation, and L2/L1×100 (%) was used as the moisture deterioration.

(1) Coating deterioration

Example 1: -4%

Example 5: -3%

Comparative Example 3: -16%

(2) Resistance to moisture degradation

Example 1: -2%

Example 5: -6%

Comparative Example 3: -8%

From the above results, it was found that in the coating deterioration test and the moisture resistance deterioration test of Examples 1 and 5, the change in inductance was sufficiently small, and the magnetic characteristics could be ensured.

The present invention has been described with reference to the above embodiments, but the present invention is not limited to the above embodiments, and can be carried out for the purpose of improvement or within the scope of the inventive concept. Improvement or change.

[Industrial availability]

As described above, the magnetic characteristics of the inductance element of the present invention are stable and are useful for realizing an element having high adhesion of the terminal conductive layer.

Claims (4)

An inductance element in which a coil is embedded in a magnetic core; the inductance element is characterized in that the magnetic core has a core body including magnetic powder and is formed by press molding, and a cover covering an outer surface of the core body At least a part of the resin layer and the metal terminal portion which is electrically connected to the coil are exposed on the outer surface of the core body without being covered by the covering resin layer; and the surface of the magnetic core is formed of a conductive material and a binder resin. The terminal conductive layer, the terminal conductive layer is bonded to the cover resin layer and the terminal portion, the cover resin layer is formed of an epoxy-modified fluorenone resin, and the epoxy-modified fluorene ketone resin comprises an fluorenone epoxy varnish. An inductance element in which a coil is embedded in a magnetic core; the inductance element is characterized in that the magnetic core has a core body including magnetic powder and is formed by press molding, and a cover covering an outer surface of the core body At least a part of the resin layer and the metal terminal portion which is electrically connected to the coil are exposed on the outer surface of the core body without being covered by the covering resin layer; and the surface of the magnetic core is formed of a conductive material and a binder resin. a terminal conductive layer, wherein the terminal conductive layer is bonded to the cover resin layer and the terminal portion; the cover resin layer is formed of a heat resistant polyester resin; and the heat resistant polyester resin comprises a phenol modified alkyd resin or a polyester fluorenone. The inductance element according to claim 1 or 2, wherein the adhesive resin of the terminal conductive layer is an epoxy resin. The inductive component according to claim 1 or 2, wherein the terminal portion is a strip-shaped body, and a strip surface is exposed on an outer surface of the core body to be bonded to the terminal conductive layer.